ASQ

Exclusive Content & Downloads from ASQ

Two Charts: Not One

Summary: [This abstract is based on the authors' abstract.]Because data coming from a typical operating process do not vary about a fixed mean, the operation of traditional control charts may be inconsistent. It is shown that a nonstationary model provides a continuously updated local mean level that can be used to produce both a bounded adjustment chart for determining when to adjust the process to achieve maximum economy and a Shewhart monitoring chart identifying assignable causes of trouble applied to the deviations from the local mean. Estimation of the mean and standard deviation are not required.

Please sign-in or register to download this information. Registration is FREE and gives you access to ASQ's articles, case studies and general information.


Other Ways to Access content:

Join ASQ

Join ASQ as a Full member. Enjoy all the ASQ member benefits including access to many online articles.

  • Topics: Statistical Process Control (SPC), Statistics, Engineering
  • Keywords: Exponentially weighted moving average control charts (EWMA), ARIMA time series models, Monitoring, Noise, Design of control charts, Shewhart control chart, Stationary process
  • Author: Box, George E. P.; Paniagua-Quinones
  • Journal: Quality Engineering